2015 ACVIM Forum Research Abstract Program

Serum BHB concentrations were measured in samples drawn at admission in 28 client-owned cats with CKD, 34 cats with HT, and 15 cats with HL, and were compared to a reference range established based on serum BHB concentrations in healthy cats. Variables of clinical relevance in each disease condition (including serum concentrations of creatinine, total thyroxine (T4), and serum activities of liver enzymes) were examined for relationships with serum BHB using Kendall's correlation. Results of urine ketone measurement by dipstick, when available, were compared to BHB measurement. Incer Serum BHB concentrations were above the reference range (>0.11 mmol/l) in 6/28 cats (21.4%) with CKD, 7/34 cats (20.6%) with HT, and 11/15 cats (73.3%) with HL. For the CKD and HT groups, this increase in serum BHB was mild in affected cats (0.12-0.26 mmol/l for CKD, 0.12-0.51 mmol/l for HT). For the HL group, this increase had a wider range (0.12-2.78 mmol/l) and was more marked, as 3/15 HL cats had a serum BHB concentration >2 mmol/l. For all groups, the percentage of cats with serum BHB concentrations above the reference limit was significantly higher than 2.5%, which would be the percentage expected for a normal population of cats (p < 0.001 for all groups). Of the clinical variables evaluated, only total T4 in the hyperthyroid group correlated positively with BHB (P = 0.03). Of 44 cats with a urine dipstick performed within 24 hours of serum BHB sampling, none were positive for ketones; however, 12/44 cats had a serum BHB concentration above the upper limit of the reference range, and 2/44 cats had a serum BHB > 2 mmol/l. Increases in serum BHB concentrations occur commonly in cats with CKD, HT, and HL, and may provide a useful index of catabolism. Furthermore, serum BHB appeared to be more sensitive than urine ketone measurement in detecting ketonemia in this population of cats. Catabolic states other than diabetes mellitus must be considered when evaluating serum BHB concentrations in sick cats.